Gavin Andresen, Chief Scientist at the Bitcoin Foundation and a correspondent of Satoshi’s, told Newsweek, “If you come out as the leader of Bitcoin, now you have to make appearances and presentations and comments to the press and that didn’t really fit with Satoshi’s personality. He didn’t really want to lead it anymore. He was pretty intolerant to incompetence. And he also realised the project would go on without him.”

There’s also the possibility that Nakamoto lost the access keys that would enable him to spend his fortune, though Andresen is doubtful toward this, saying that Nakamoto was “too disciplined” to make a mistake as simple as that.

Here’s the far more likely explanation on why that money remains undisturbed:

If Nakamoto ever sells his Bitcoin fortune, he would likely have to do so at a legitimate Bitcoin bank or exchange, which would not only give away his identity but alert everyone from the IRS to the FBI of his movements. While Bitcoin lets its users conduct transactions anonymously, all transactions can be viewed transparently online — and everyone is watching Nakamoto’s Bitcoin to see if he spends it, says Andresen.